Chronic hyperglycemia is one of the defining characteristics of diabetes mellitus. Hyperglycemia is a condition in which there is an elevated blood glucose concentration. An elevated blood glucose concentration may result from impaired insulin secretion from the pancreas and also, or alternatively, from cells failing to respond to insulin normally. Excessive glucose release from the liver is a significant contributor to hyperglycemia. The liver is responsible for approximately 90% of the glucose production and 33% of glucose uptake, and derangements in both in type 2 diabetes contribute to hyperglycemia in the fasting and post-prandial states.
Type 1 diabetes mellitus results from autoimmune destruction of the pancreatic beta cells leading to inadequate insulin production. Type 2 diabetes mellitus is a more complex, chronic metabolic disorder that develops due to a combination of insufficient insulin production as well as cellular resistance to the action of insulin. Insulin promotes glucose uptake into a variety of tissues and also decreases production of glucose by the liver and kidneys; insulin resistance results in reduced peripheral glucose uptake and increased endogenous glucose output, both of which drive blood the glucose concentration above normal levels.
Current estimates are that approximately 26 million people in the United States (over 8% of the population) have some form of diabetes mellitus. Treatments, such as medications, diet, and exercise, seek to control blood glucose levels, which require a patient to closely monitor his or her blood glucose levels. Additionally, patients with type 1 diabetes mellitus, and many patients with type 2 diabetes mellitus, are required to take insulin every day. Insulin is not available in a pill form, however, but must be injected under the skin. Because treatment for diabetes mellitus is self-managed by the patient on a day-to-day basis, compliance or adherence with treatments can be problematic.